U.S. Frost Dates by Weather Station

NOAA station USC00113335 · Illinois

Frost Dates for Galva, IL

NOAA weather station Galva (USC00113335), Illinois · elevation 810 ft (247 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season166 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Galva, ILSpring: a frost after April 12 in 9 years out of 10, after April 26 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 12 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 166 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 12Frost season at Galva, ILSpring: a frost after April 12 in 9 years out of 10, after April 26 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 12 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 166 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 12
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 11September 25
50% (typical)April 26October 12
90% (likely)April 12October 24
Frost-free season (32°F, 50% chance)
166 days
Hard frost (28°F), last in spring, 50% chance after
April 16
Hard frost (28°F), first in fall, 50% chance before
October 22

The last 15 years (2006–2020 normals)

Typical last frost April 27 (1 day later than the 30-year normal), typical first fall frost October 14 (2 days later). Frost-free season 170 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring at Galva: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 5, 30% May 2, 40% April 29, 50% April 26, 60% April 24, 70% April 21, 80% April 17, 90% April 12. Observed last spring frost in recent years: 2024 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 11Apr 26Apr 122024: April 21Fall at Galva: chance of a frost before this dateFall, chance of a frost before the date: 10% September 25, 20% October 2, 30% October 6, 40% October 10, 50% October 12, 60% October 14, 70% October 16, 80% October 19, 90% October 24. Observed first fall frost in recent years: 2021 October 23, 2022 October 8, 2023 October 30, 2024 October 16.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 25Oct 12Oct 242021: October 232022: October 82023: October 302024: October 16
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021incomplete recordOctober 23
2022incomplete recordOctober 8
2023incomplete recordOctober 30
2024April 21October 16
2025incomplete recordincomplete record
2026incomplete recordseason not over yet

What these dates mean

May 11, with a 10 % chance of a light frost later, is the cautious spring date for setting out tender crops in Galva. Planting after this date gives a gardener a low risk that a 32 °F frost will still occur.

The 50 % light-frost dates—April 26 in spring and October 12 in fall—mark the point where a frost is equally likely to appear before or after each date; they are useful reference points but not frost thresholds. For a cautious fall schedule, September 25, with a 10 % chance of a light frost earlier, is the date to aim for when finishing harvest of tender crops. The median hard-frost dates are April 16 and October 22; a hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F. These dates reflect the 27-year record for this station.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after May 11" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before September 25" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Galva, ILNumbered nearest stations: 1 — Kewanee, IL — 8 mi; 2 — Geneseo, IL — 20 mi; 3 — Galesburg, IL — 24 mi; 4 — near Moline, IL — 32 mi; 5 — Princeton, IL — 33 mi.IA25 mi · 40 km1. Kewanee, IL — 8 mi12. Geneseo, IL — 20 mi23. Galesburg, IL — 24 mi34. near Moline, IL — 32 mi45. Princeton, IL — 33 mi5
  1. Kewanee, IL 8 mi (14 km)
  2. Geneseo, IL 20 mi (32 km)
  3. Galesburg, IL 24 mi (39 km)
  4. near Moline, IL 32 mi (52 km)
  5. Princeton, IL 33 mi (53 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 41.1739, -90.035.